This study will compare the immediately delivery (within 6 hrs. of head injury) to delayed delivery (48 hrs. after head injury) of TPN in regards to 1) safety; 2) neurologic outcome; 3) hypermetabolic response; and 4) lean body mass. The experimental design is a prospective, randomized trial with 2 groups (20 patient in each group). We will assess hyperalimentation tolerance (Liver Function Profile, Serum Triglycerides, Osmolalities); hypermetabolism (glucagon, cortisol growth hormone, urine catecholamines, urea) & lean body mass.